RU2447908C2 - Braiding closure having repetitive enlarged segments separated by junction areas - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medical equipment. A method for manufacturing of a device involves braiding of shape memory metallic fibres in a tubular metal lath to make a braided configuration. A lath end is fixed to prevent untwisting. The lath is arranged in or on a moulding structure of a first preset shape containing a number of enlarged spherical or ovaloid segments chained by intermediate links. The moulding structure is heated to higher temperature for a period of time sufficient for heat shrinkage of the lath in the first preset shape for keeping the first preset shape when the medical device is found in a relaxed condition. The metal lath of the first preset shape is modelled into a second preset shape by rolling up to keep the second preset shape when said device is found in a relaxed condition. What is disclosed is a device produced by this method.

EFFECT: decreased press-through efforts and increased thrombus formation rate.

31 cl, 9 dwg

Description

BACKGROUND OF THE INVENTION

I. Field of the invention:

In General, the present invention relates to intravascular devices for the treatment of certain medical conditions, and more particularly relates to intravascular occlusion devices for the selective occlusion of a vessel, channel, lumen or cavity in any part of the cardiovascular system of the body where you want to stop the flow of blood. Devices made in accordance with the invention are particularly well adapted for delivery through a small diameter flexible catheter or the like. to a remotely located treatment site in the patient’s cardiovascular system within the patient’s body to quickly plug the site in order to provide a high metal to volume ratio. The device can have a high ratio of delivery distance to deployed length and can reach more winding places than traditional clogging devices.

II. Description of the technical field:

Various medical procedures use a wide variety of intravascular devices. Certain intravascular devices, such as catheters and catheter guides, are typically used simply to deliver fluids or other medical devices to specific locations within the patient’s body, such as a sample location within the cardiovascular system. Other often more complex devices are used to treat specific conditions, such as devices used to remove clogged vessels or to treat vascular defects such as aneurysms and the like. In certain cases, it may be necessary to clog the vessel, lumen, channel, opening, or cavity of the patient, for example, to stop the flow of blood through it.

Mechanical embolization devices are well known in the art and are commercially available for blocking blood vessels at various places in the vasculature. Patent No. 6123715 by Amplatz and Patent No. 5725552 by Kotula disclose an intravascular occlusion device made of a Nitinol braided metal mesh that has been expanded into shape using heat shrinkage, but which can be compressed for delivery through a catheter to the treatment site, resulting in ejection From a delivery catheter, the device itself expands inside the vasculature to block the blood flow at the treatment site. Details of various designs and configurations, as well as methods for manufacturing and using the device, are described in detail in the above patents and are hereby incorporated by reference in their entirety.

Although the plugging devices described in the patents of Amplatz and Kotula are quite effective, significant improvements can be made to them. Amplatz’s patent No. 5725552 in FIGS. 5A and 5B shows an elongated vascular occlusion device made of a braided metal mesh into which two spaced-apart disk elements of increased diameter are embedded between the ends. Disc elements are designed to cling to the inner surface of the vessel in order to cause vessel thrombosis through the interaction of blood and Nitinol wire mesh. In diameter, the size of the disk elements in a freely expanded state should be slightly larger than the inner diameter of the vessel to help the device fix. This gives the load from the desire to braid Nitinol to expand further to be imparted against the wall that limits the lumen in the body in order to fix the device in place.

Preferably, the disks are spaced apart in order to provide stability to the device inside the vessel and to prevent the device from rotating across the axis of the vessel. The device is elongated for delivery through the lumen of the catheter by pulling the lugs at the ends of the wire from each other. This operation reduces the diameter of the device for insertion into the catheter. The delivery system consists of an elongated wire with a screw end, which fastens the connected screw end with a tip at one end of the wire on the device, which allows the device to be pushed through the delivery catheter. When the device leaves the distal end of the catheter, the device itself straightens to a remembered shape, predefined by heat shrink. The threaded connection allows you to control the device for returning, changing position or selective movement after the device is correctly placed in the vessel.

The diameters of the disks in the expanded state are slightly larger in diameter than the diameter of the lumen of the catheter for delivery. The stiffness of the discs and their large diameter contribute to the force required to push the device through the delivery catheter. Additionally, since the device needs to be pushed from the proximal end and not pulled from the distal end, the device is squeezed slightly, this leads to a slight expansion from the outside and also contributes to the force required for delivery. To reduce this load, perhaps the clearance of the catheter for delivery should be increased.

However, this causes the delivery catheter to be stiff and less capable of easily passing through tortuous vessels than otherwise. Also, the value of the metal density for a given occupied volume can act on the speed with which thrombosis will develop to clog the vessel. As a rule, the more metal is exposed for blood flow, the higher the rate of thrombosis; also a larger amount of metal usually corresponds to a lower rate of restoration of the lumen of the device after the implant. The Amplatz device has a relatively low metal to volume ratio compared to the patentable design described herein, and therefore often uses the addition of polyester fiber to increase the rate of thrombosis.

Another capping device in the prior art is described in US Pat. No. 6,033,423 by Ken et. al "Multiple Layered Occlusive Coils". This patent describes a vasoconstrictor device for blocking a vessel or aneurysm, especially in the brain. The closure device is a small diameter wire spiral, preferably 0.010-0.018 inches in diameter, preferably made of a shape memory material such as Nitinol. A wire spiral is wound around itself and thermally accelerated to maintain a shape that occupies a volume in three dimensions to clog the vessel. For insertion through a catheter, the spiral is stretched to reduce its profile to the profile of the turn itself. The turns are very flexible and can pass through the microcatheter through the tortuous vessels of small diameter, which are found, for example, in the brain. Since a small diameter of the coil must be supported to pass through a small-diameter catheter, the length of the coil to fill a given volume is large enough. The usefulness of using such small spirals in large volumes, such as aneurysms, found outside the neurovascular network or in a cavity of significant volume, is reduced due to the small volume occupied by these microcoils.

Thus, it is useful to provide an improved device for blocking the vasculature that offers a better ability to fill the volume for a given implant length, a catheter for delivering a smaller diameter than traditional systems of the prior art, less effort to push the device through the delivery catheter, increased ability to pass tortuous vessels and an increased rate of thrombogenesis by providing a greater ratio of metal to volume.

In addition, in certain cases, it will be useful to be able to deliver the device using the “wire” approach, which is well known in the field of angioplasty catheters. It will also be advantageous to have greater shape retention power by adding an optional shape retention wire to provide or assist in the formation of the final shape of the vessel clogging device.

SUMMARY OF THE INVENTION

The present invention relates to an inventive solution to the above problems in the prior art. Using a circular knitted braid made of a shape memory material such as Nitinol, and the same methods of production, molding and heat treatment and delivery as are described by patents 6123715 by Amplatz and 5725552 by Kotula et. al., the present invention relates to a flexible, low profile vascular occlusion device having the ability to fill a large volume and a high metal content for rapid occlusion. In the cited patents, a braided circular knitted metal mesh having an expanded predefined configuration and an elongated compressed configuration with a reduced diameter for delivery through a catheter to a treatment site is shaped to create a clogging of a pathological opening in an organ or vessel of the body. A woven metal mesh has a memory property, on the basis of which, in a free state, the medical device tends to return to the specified extended predefined configuration. The closure device further comprises a first shape formed from a circular braided mesh consisting of a repeating pattern of sections with an increased diameter or volume separated by small diameter joints, and a second overall shape of the device consisting of a first shape formed by itself in various volumetric shapes for plugging vessel.

In another embodiment, the forming wire is coaxially contained within the circular knitted braid and provides or promotes the formation of a second common final shape of the device.

The present invention is well adapted to selectively clog a vessel, lumen, channel, or cavity. A few examples, without limitation, are aneurysm, left atrial ear in patients with left atrial fibrillation, arterial-venous fistula (AVF) or arterial-venous malformation (AVM), or any vessel that needs to be blocked to prevent blood flow through it. Other options include treating an atrial septal defect (DMF), an interventricular septal defect (DMF), open ductal ductus arteriosus (OBP), or open ductus arteriosus (OAP).

When forming an intravascular occlusion device from an elastic metal mesh with wires, a lot of elastic threads are provided when formed using a braiding machine to create an elastic material that can be thermally processed mainly to give the desired shape. This braided mesh is then deformed so that it generally matches the surface shape of the molding part, and the braided mesh is thermally treated by contacting the surface of the molding part at an elevated temperature to give the first molding form. In space, in a preferred embodiment, the first molding form is a repeating segment of an increased diameter or volume of an oval or spherical shape and with the separation of adjacent enlarged volumes consisting of a braid, using small diameters functioning as joint sections between the increased volumes. The time and temperature of the heat treatment are chosen mainly to bring the braid mesh into its deformed state. After heat treatment, the mesh is taken out of contact with the molding part, and basically it will retain its shape in an unpressed state. The elongated molded element is additionally given, by heat treatment, a second shape by folding the elongated element around itself into any of a plurality of three-dimensional shapes, which are discussed in the following detailed description. The second heat treatment of the braid mesh determines the unfolded state of the medical device, in which it is deployed in the patient’s body through the catheter and placed in the desired intended place.

In another embodiment of the invention, the first heat-treated braid form is achieved as described above, but the final shape of the device is achieved by using a shape memory wire whose dimensions are suitable to fit inside the first heat-treated braid and in the layout heat treated to give the second desired final shape to the central axis of the braiding device. In this embodiment, the wire is inserted into the heat-treated braid of the first form prior to the second heat treatment, and the distal end of the braid is attached to the distal end of the wire at the clip of the distal end of the braid. The proximal end of the wire dangles freely inside the proximal part of the braid. During use, when the device is ejected from the distal end of the delivery catheter, the profile wire and braid will take on the stored final shape of the device.

Alternatively, the shape memory wire can be separately heat treated to shape the end device or second shape and then inserted into the braid having the first shape. The composite device will take the final second form of the device, based on a profile wire, which retains its shape better than the braided joints.

Embodiments of the present invention provide improvements in the specific form with respect to medical devices of the prior art that can be manufactured in accordance with the present invention, aimed at blocking vessels with specific anatomical conditions. Such devices according to the invention are made of braided metal mesh and have a deployed configuration and a compressed configuration. In use, the catheter can be located in the channel in the patient’s body and advanced to a position where the distal end of the catheter will be near the treatment site to treat a physiological condition. A medical device that has been given a predetermined shape and made in accordance with the process described above can be compressed by pulling the ends to the sides and can be inserted into the lumen of the catheter. In use, the device is pushed through a catheter and withdrawn from the distal end, after which, due to its memory property, it will tend to largely return to its expanded state near the treatment site.

According to the first of these embodiments, the closure device is coiled into a spiral or coil, the length of which ensures its longitudinal stability and sufficient fixation inside the vessel or cavity. The size of the device is slightly larger than the vessel or cavity for which it is intended to provide an outwardly directed expansion force with respect to the walls of the vessel or cavity to hold the device in place and prevent embolization of the device. Alternative forms include a turn inside the turn to provide a denser filling of the vessel or, alternatively, a device in the form of turns, the diameter of which varies from small to large. Another option is a partially spherical final shape of the device. If there is, then there are minor manufacturing limitations on the shape of the device. Devices can be made to take the form of aneurysms of any size and shape. Alternatively, it may be sized to fit the left atrium or other vascular abnormality.

One embodiment provides means for delivery through a wire, while a plugging device is located within the delivery catheter.

The closure device according to the invention will clog the vessel, channel, lumen or cavity quickly due to the high ratio of metal to volume filling and due to the fact that the volume is filled with braided parts with an increased diameter that interact with blood and also limit blood flow. The device can be pulled out for delivery through a small-diameter catheter and, thanks to its flexible properties, can easily pass through winding paths inside the human body.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a side view of a segment of a braided tubular structural member of wire with shape memory before being shaped and heat treated.

Fig. 2A is a side view of a sample of the tubular element of Fig. 1 after molding and heat treatment to give memory.

Fig. 2B is a side view of another sample of the tubular element of Fig. 1 after molding and heat treatment.

Fig. 3A is a side view of a patentable device in the form of a simple spiral.

FIG. 3B is a side view of a shape memory wire that can be used as a component of an alternative embodiment to create the shape shown in FIG. 3A.

Fig. 4A is a side view of an alternative embodiment of a patentable device having a spiral shape consisting of alternating spirals of smaller and larger diameters.

FIG. 4B is a side view of a shape memory wire that can be used as a component of an alternative embodiment to create the shape shown in FIG. 4A.

Fig. 5A is a side view of an alternative embodiment of a patentable device having a continuous small diameter spiral inside the device, coiled into a larger diameter spiral.

FIG. 5B is a side view of a shape memory wire that can be used as a component of an alternative embodiment to create the shape shown in FIG. 5A.

6A is a side view of a patentable device in a shape close to a sphere.

FIG. 6B is a side view of a shape memory wire that can be used as a component of an alternative embodiment to create the shape shown in FIG. 6A.

7 is a partial cross-sectional view of an alternative embodiment of a patentable device comprising a wire with a predetermined shape memory inside the braid to assist in shaping the device.

Fig. 8 is a partial cross-sectional view of another alternative embodiment of a patentable device adapted for delivery through a wire.

Figure 9 is a cross-sectional view of the obturator of the present invention, partially stretched from the distal end of the delivery catheter filling the thoracic aortic aneurysm.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to an improved transdermal catheter guiding an intravascular occlusion device for use in the vasculature in patients' organisms, for example, in blood vessels, channels, lumens, an opening in a tissue, cavity, and the like. When creating the medical device according to the invention, the metal mesh is made of many wire threads having a predetermined orientation relative to the threads.

Metallic filaments define two sets of generally generally parallel spiral filaments, in which the filaments from one set have “hand”, i.e. direction of rotation opposite to the direction of rotation of another set. This defines a generally circular knitted mesh, known in the textile industry as a tubular braid. The previously discussed patents of the authors Amplatz and Kotula describe medical devices and methods for manufacturing such devices in detail, so only a general discussion is given.

The inclination of the wire strands (i.e., the angle defined between the turns of wire and the braid axis) and the mesh pitch (i.e., the number of points of intersection of the wire per unit length) can be set in accordance with the requirements of a particular application. The wire strands of the metal mesh used in the present method should be made of a material that is resilient and heat treatable in order to substantially give the desired shape. Materials suitable for this purpose include a low thermal expansion cobalt-based alloy known in the art as Elgeloy, high-temperature high-strength nickel-based superalloys commercially available from Haynes International under the trade name Hastelloy, heat-treated nickel-based alloys that are sold under the name Incoloy at International Nickel, and many different grades of stainless steel. An important factor in choosing the right material for the wire is that the wires retain a suitable degree of deformation created by the molding surface during a predetermined heat treatment.

Another class of materials that meet these requirements are the so-called shape memory alloys. One particularly preferred shape memory alloy for use in the present process is a nickel-titanium alloy called Nitinol®. NiTi alloys are also very resilient - they are called “superelastic” or “pseudoelastic”. This resilience will help the device of the invention return to this deployed configuration for deployment while removing limitations, say, in the lumen of the delivery catheter.

When creating a medical device in accordance with the invention, a piece of metal mesh of an appropriate size is cut from a larger piece of mesh, which is created, for example, by braiding wire strands to create a long tubular braid. When trimming the mesh to the required size, care must be taken to ensure that the mesh does not untangle.

You can solder, solder, weld or otherwise fix the ends of the desired length together (for example, using biocompatible cementitious organic material) before cutting the braid.

When a piece of metal mesh of the appropriate size is obtained, the mesh is deformed, as a rule, to fit the surface of the molding part. The deformation of the grid will reorient the relative positions of the filaments of the metal mesh from their initial order to the second reoriented configuration. The shape of the molding part should be selected to deform the mesh substantially into the desired shape.

When the molding part is connected to a metal mesh, which generally corresponds to the molding surface of the part, the mesh can be heat treated while it remains in contact with the molding surface. Suitable heat treatment methods for Nitinol wire to give the desired shape are well known in the art. It was found that heating the Nitinol mesh from about 500 to about 550 ° C for about 1 to about 30 minutes, depending on the ductility or harness of the device being manufactured, will tend to give the mesh its deformed state, i.e. a state that corresponds to the molding surface of the molding part. At lower heat treatment temperatures, the time will increase (for example, about 1 hour at about 350 ° C) and at higher temperatures, the time will decrease (for example, about 30 seconds at about 900 ° C).

After heat treatment, the mesh is taken out of contact with the molding part, and it will basically retain its shape after deformation. We now turn our attention to FIG. 1, which illustrates the braided tube, how it is woven, before any shaping during the heat treatment. The wires are preferably made of Nitinol alloy and can vary in diameter from 0.001 to 0.006 inches, preferably from 0.0015 to 0.003 inches in diameter. The number of wires that make up the braid can be from 8 to 144, preferably 8-32. The braid is made around a core 3-4 mm in diameter to obtain the smallest braid using 8-16 wires and around a larger core for more wires or wires of a larger diameter.

Fig. 2A illustrates a first heat-shrinkable shape of the inventive device 11. The first heat-shrinkable mold consists of a braided tubular element 14 expanding into a segment 15 of a larger diameter or volume in a repeating pattern with a segment 16 with a reduced diameter of the braid between adjacent expanding sections 15. The expanded segments 15 serve the aspect of filling the volume according to the invention and segments 16 with a reduced diameter serve as sections of the joint, which allow the tubular element to turn around circle itself in a variety of configurations. FIG. 2B shows the inclination B between repeating sections other than those shown in FIG. 2A.

There are no requirements for a specific initial diameter of the initial braiding tube relative to the first shape being created. For example, the original braided tube may be larger or smaller than the first heat-shrink form, provided that the desired shape can be formed, and provided that the device can be stretched for insertion into the delivery catheter and the angle of the braid in the extended segment has the desired outward resistance to compression.

There are also no specific requirements for the slope between the extended sections or between the joint sections to be the same. For certain configurations that need to be formed in the final shape of the device, it may be highly desirable to change the location of each type of segment in a specific position along the length of the device, which will be discussed in detail below.

Preferably, the expanded portions are either oval or spherical in shape, although they can also be of any other shape, and the expanded shape may have a variable volume or diameter along the length of the device.

As shown in FIG. 7, the ends of this braided metal mesh device 70 are welded or secured together by clips 77 to prevent abrasion. Of course, the ends can be held together by other means well known to those skilled in the art. A clip 77, holding the wire strands together at the proximal end of the device 70, also serves to connect the device to the delivery system 76. In the shown embodiment, as a rule, the clamp 77 of a cylindrical shape has a recess to accommodate the ends of the metal mesh to thoroughly prevent the movement of the wires contained in the woven mesh relative to each other. The clamp 77 also has a helical surface inside the recess. The screw recess is adapted to accommodate and engage the screw distal end 78 of the delivery device 76. The distal clamp 72 also has a recess to accommodate the distal ends of the wire. The clamps may optionally be made of a non-transparent material, such as a platinum-iridium alloy, or may be stainless steel or other well-known materials.

Fig. 8 is a plugging device adapted for delivery through a wire. Optionally, but not considering it as a requirement, the device 90 shown in FIG. 8 can be configured with assemblies (assemblies) 82 and 87 of clamping elements at both ends of the wire, whereby the arrangement comprises a hollow outer and inner sleeve. The dimensions of the distal outer clamping member are such that the inner diameter is sufficient to accommodate the ends of the braided wire surrounding the inner clamping member before stamping, or alternatively, instead they can be fastened between the clamping members or welded. The inner clamping element is tubular and its dimensions are such that the inner diameter is able to freely pass through a wire guide 91, which is usually 0.010-0.018 inches in diameter, preferably 0.010 inch wire or cable. The proximal outer clamping member is shown with an external screw thread 88 for reversibly attaching the delivery system 89, which is preferably a nylon block copolymer such as Pebax, with a 0.001-inch stainless steel braid over the inner extruded Pebax tube, with another other outer layer Pebax covering the braid. This design is typical of intravascular guide catheters where flexibility and torque transmission are required. Pebax's inner diameter is sufficient to allow wire guide 91 to pass freely.

Now pay attention to figures 3-6A and 6B. Now the discussion will concern the shrinkage of the second or final form of the device. Four examples are discussed (without limitation) of the specific final forms of the device, as well as three main methods of manufacturing the device. In the first main method of forming the second or final form of the device, the device, for example, from FIG. 2A, which has the first formed shape, is wrapped around itself in the second or final form of the device and held in place during the second heat shrink process to maintain its shape when cooled and taking off the form.

In the second main manufacturing method of the device, a separate wire with shape memory 73 (FIG. 7) preferably of 0.005-0.010 inches diameter in a Nitinol alloy (in the range of 0.003-0.020 inches) is placed coaxially with the braid having the first formed shape, and the braiding and wire layout placed in a mold that holds the assembly wire in the axis shape of the desired final form of the braiding device. In this design, either before or optionally after heat treatment of the arrangement, the ends of the wire 73 and the distal braided wire are secured inside the distal clamp 72 by crimping, soldering, welding or other well-known means. The proximal end of the wire will coincide with the length of the braid or slightly shorter than the length of the braid when the braid is in its free deployed state. The proximal end of the wire loosens freely inside the proximal portion of the sheath to allow the sheath to stretch for placement in the delivery catheter, as shown in FIG. 7.

In a third main method for manufacturing the device, the shape memory wire can be heat treated separately in the form compressing the wire to the final or second shape of the device. After the wire remembers the required shape in heat treatment, the braid with its first shape specified during heat shrinkage is pulled onto the wire until the distal end of the wire and the distal end of the braid are aligned. The wire 73 and the distal end of the braid wire are secured in the distal clamp 72 by crimping, soldering, welding or other well-known means. The proximal end of the wire will coincide with the length of the braid or will be slightly shorter than the length of the braid when the braid is in its free deployed state. The proximal end of the wire loosens freely inside the proximal portion of the sheath to allow the sheath to stretch for placement in the delivery catheter, as shown in FIG. 7. The proximal ends of the braided wire are fixed in the proximal clamp 77. The composite device will take the final second form of the device based on the profile wire, which retains shape better than the joints in the braid.

On figa the second form of the clogging device consists of a coil or spiral winding from the first form of a given length and diameter. For stability inside the vessel, the length should be a minimum of approximately two diameters. A device of this form can be manufactured using any of the first, second or third main manufacturing method. Fig. 3B illustrates a longitudinal view of the shape of the forming wire 13 obtained by a separate heat shrink, which can be used to make a device with 3A using a second or third main manufacturing method. Optionally, the ends of the spiral can be shaped so that the last few expanded sections 15 bend with a smaller radius in order to clog the input and output of the coil to further limit the current. The shapes shown in FIGS. 3-5 are particularly suitable for plugging a tubular vessel and are capable of being adapted to bend or bend in a vessel. The form of FIG. 6 can be used in a vessel, but can be adapted to clog a cavity such as a left atrial ear (LAA) or possibly an aneurysm.

4A, the second form of the plugging device 20 consists of a winding or spiral winding having variable small and large diameters of the first shape of a given length. By using variable diameters, more complete clogging can be achieved to fill vessels having internal diameters at least two times the diameter of the enlarged volume portions 15. For stability inside the vessel, the length of the spiral device should be at least about two times the diameter. A device of this form can be manufactured using any of the previously described first, second or third main manufacturing method. Fig. 4B is a longitudinal view showing the shape of the forming wire 23 obtained by separate heat shrinkage, which can be used to manufacture the 4A device using a second or third main manufacturing method. Alternatively, the device may have 3 or more variable diameters for larger vessels with respect to the diameter of the enlarged segment 15.

5A, the plugging device 30 has a second shape, consisting of a complete inner coil surrounded by an outer coil. This provides a compact metal arrangement for blocking a vessel or cavity, such as an aneurysm or left atrial ear. The structure can be made using any of the 3 main methods discussed previously and it will fill vessels having a diameter of at least 4 times the diameter of the expanded sections 15. FIG. 5B is a longitudinal view showing the shape of the forming wire 33 obtained by separate heat shrink which can be used to fabricate a 5A device using a second or third main manufacturing method. The device may be configured to first unwind the inner spiral and then the outer spiral, or vice versa. Additionally, it may be desirable to deploy both spirals in the distal proximal direction by providing a long connecting segment 16 that extends from the end of the first turn to the distal end of the second turn to allow the second turn to also unfold in the distal proximal direction.

6A illustrates a shape of a plugging device 40 that has a second shape close to a spherical shape. The mold is made by twisting the device with the first heat-shrink form around itself into the desired shape, followed by heat-shrink the twisted form, while the form or other restraining means holds it in place. As indicated above, a twisting pattern can be selected which is required to form a shape such as an ovaloid, possibly to fill an aneurysm or cavity of such a shape, for example, an atrial left ear.

FIG. 6B illustrates a separately heated shaped wire that can be used to make the device shown in FIG. 6A using a second or third main manufacturing method.

Since it may be necessary to fill the vessels, aneurysms and cavities of many different sizes, the choice of the diameter of the braided wire, the number of wires in the braid and the size of the expanded sections can be selected relative to the size of the vessel. Preferably, the expanded segment is small relative to the maximum width of the vessel or cavity. For example, an oversized segment should be in the range 0.4-0.1 (preferably 0.3-0.2) of the width of the vessel or cavity to be filled. The final size of the device should be slightly larger than the vessel or cavity to be filled in order to exert outward pressure on the wall of the vessel or cavity in order to sufficiently hold the device in place.

Depending on the desired final shape of the device, the length of the joint segment can be changed to achieve the most accurate fit or placement of the extended sections relative to adjacent extended sections. As shown in FIG. 5A, the outer spiral is located adjacent to the inner spiral. The length of the joint segment of the second spiral may differ from the inner spiral to achieve better packaging or placement of the extended sections. This close placement provides a high metal density and an improved current limitation for rapid clogging (thrombosis) of the vessel.

Those skilled in the art will appreciate that in order to accelerate clogging with a vascular device, the device may be coated with a suitable thrombotic agent, filled with polyester fiber, or braided with an increased number of strands of wire. Prior art devices preferably use polyester inside the braiding device. When located inside the braid, its fiber can easily be flattened when the device is delivered through a catheter. The interwoven fiber, by attaching to the clot, holds the clot tightly inside the device when it forms a blockage.

FIG. 8 illustrates a delivery device that can be used to push the closure device 10, 20, 30, or 40 through the lumen of the catheter 92 or the casing of a long intubator to deploy in a channel in a patient. When the device is deployed from the distal end of the catheter, the device will still be held by the delivery device 79 or 89 in FIGS. 7 or 8, respectively. When confirming the correct placement of the device in the vessel, the handle of the delivery device can be rotated around its axis to unscrew the clip 77 or 87 from the delivery device 79 or 89, respectively.

By keeping the plugging device attached to the delivery vehicles, the operator is still able to retract the device for re-positioning if it is determined that the device was not positioned correctly on the first attempt. This screw fastening will also enable the operator to control the deployment of the device 10 from the distal end of the catheter. When the device leaves the catheter, it will tend to resiliently return to the final expanded shape, which was set when the mesh was subjected to heat shrink. When the device springs into this shape, it may tend to act on the distal end of the catheter, effectively pushing itself in the distal direction beyond the end of the catheter. This spring action may possibly result in improper positioning of the device. Since the screw terminal 77 or 87 (FIGS. 7 or 8) enables the operator to maintain the retention of the device during deployment, the spring action of the device can be reduced and the operator can control the deployment in order to ensure proper positioning.

Fig. 7 illustrates a plugging device made in a second or third main method comprising separately heat-shrinking a device forming wire 73 attached to a terminal 72 at a distal end of a wire by crimping, stamping, gluing, soldering or other means. The proximal end of the wire 73 hangs inside the braid and is shorter than the braid when it is stretched for delivery through the catheter 92 (Fig. 8). The delivery device 79 has a handle 76 of wire or wire with a connecting device 78 at the distal end with an external thread that connects to the internal thread on the clip 77 of the wire.

FIG. 8 illustrates a partial sectional view of a system 90 consisting of a delivery device 89 of a plugging device 80, a wire guide 91, and a delivery catheter 92. In this embodiment of the device 80, the design has been modified for delivery through the wire. The clips 87 and 82 of the proximal and distal ends consist of an inner sleeve and an outer sleeve. The inner sleeve has an inner diameter that allows you to freely slide along the wire guide. The size of the outer sleeve is selected so as to fit on the end of the wire and the inner sleeve. The end of the wire is placed between the two bushings and pressed, stamped, welded or attached in place to keep the wires from being untangled. The proximal clamp 87 comprises a thread 88 that matches the screw connection on the delivery device 89, which is preferably an extruded tube made of a nylon block copolymer such as Pebax, reinforced with a 0.001-inch braided wire embedded in the Pebax during co-extrusion. This design is typical of guiding catheters that require flexibility and torque transmission. Optionally, the delivery device may be made of round or flat stainless steel wire, has a clearance sufficient for free passage of the wire guide, and is coated with a thin polymer tube, such as a shrink film tube, to contain a spiral and provide torque transmission with flexibility and push effort. The distal screw connector is connected by welding or other means to the spiral distal end of the delivery device for reversible attachment to plugging device 80. The spiral handle of the delivery device may be coated with PTFE to reduce friction between the spiral and the wire guide. As the handle of the delivery device, a small diameter hypotube with an inner diameter can also be used to accommodate the wire guide passing through it.

The delivery catheter may be a simple extruded tube, preferably made of Pebax. The tube has a clearance, the size of which allows the plugging device and the delivery device to pass. The delivery catheter may have a shaped tip to provide a predetermined position for the closure device when delivered to an aneurysm, as shown in FIG. 9. To improve the response to the rotation of the delivery catheter for monitoring the tip, the Pebax tube may comprise a 0.001 stainless steel braid wire embedded in the Pebax polymer, like a guide catheter. In some cases, the guide catheter itself, or possibly a diagnostic catheter or long sleeve, can serve as a delivery device.

In use, the plugging device 80 (FIG. 8) is connected to the delivery device 89 by a screw device. The proximal end of the delivery device 89 is attached at the rear to the distal end of the delivery catheter 92. The closure device 80 is stretched by this movement and decreases in diameter and enters the proximal end of the delivery catheter 92. System 90 may be transported in this configuration due to ease of use. Access (usually via the femoral artery) to the arterial system is performed using the well-known Seldinger technique. An arterial casing is placed in an artery. In the case of delivery through the wire, as shown in Fig. 8, the wire guide is first inserted through the casing and into the artery. The proximal end of the guidewire is attached at the rear through the distal tip of the plugging device, a small portion of which is facing out from the distal end on the delivery catheter. The delivery catheter comprises a plugging device and the delivery device is advanced forward over the guide wire, through the casing and into the artery. The wire guide is advanced and carried through the vasculature to the intended site. The delivery catheter is advanced until the distal tip is located at the intended location. The guide wire may be removed before the device 80 is advanced forward from the delivery catheter, or may be removed after the clogging device is partially inside the vessel or cavity to be filled. Then, the device 80 is advanced forward by pressing on the delivery device 89 until the entire device 80 is placed as required. If the device is positioned correctly, the delivery device is unscrewed by rotation of the closure device, and the delivery catheter and delivery device are removed. If the device is not initially positioned correctly, device 80 can be pulled back to delivery catheter 92 and try again to reposition the device as soon as necessary, provided that the screw connection is retained. When the screw connection is separated, the device cannot be returned to the catheter 92.

In the case of a non-wire delivery device, as shown in FIGS. 7 and 9, the delivery catheter can be advanced along the wire guide since the closure device and the attached delivery device are not previously inserted into the catheter. When the delivery catheter is positioned as required, the wire guide can be removed from the body, and a plugging device and delivery device can be inserted into the proximal end of the delivery catheter. This can be accomplished by placing the intubator tear-off sleeve over the distal end of the delivery device before attaching it to the plugging device. The endotracheal sleeve has an outer diameter that is slightly smaller than the inner diameter of the delivery catheter. A screw connection is made between the plugging device and the delivery device and the plugging device is extended into the tear sleeve. From within the sleeve, the closure device may be routed to a conventional Luer lock connector leading to a lumen at the proximal end of the delivery catheter 92. Advancing the delivery device delivers the closure device through the delivery catheter. Now the sleeve of the intubator can be torn from the delivery device and removed. When the delivery catheter is in place, the delivery device can be advanced forward to deliver the closure device to the intended location in the vessel or cavity to be blocked.

Angiography is usually used to visualize devices and catheters in catheter procedures during delivery. If desired, the tips may be radially opaque or radially opaque marks may be added to the plugging device. Typically, the amount of metal in these plugging devices can be seen on fluoroscopy. To determine when blood flow through a vessel or cavity has been stopped by thrombosis, a radio-opaque dye can be used.

Although the device will strive to resiliently return to its original deployed configuration (i.e., to its shape prior to compression for passage through the catheter), it should be understood that it may not always fully return to this shape. For example, the device is intended to have a maximum outer diameter in its deployed configuration, at least up to and preferably larger than the inner diameter of the lumen in which it must unfold. If such a device is deployed in a vessel having a small clearance, the clearance will limit the complete return of the device to its expanded configuration. However, the device will be deployed correctly, as it will cling to the inner wall of the lumen in order to fit the device there, as described in detail above.

If the device is to be used to permanently clog the channel or cavity in the patient’s body, for example the devices 10, 20, 30, 40, 70 and 80 described above, maybe someone can simply disconnect the delivery system by disconnecting the reversible connection to the device and removing the catheter and delivery devices from the patient’s body. This will leave the medical device deployed in the patient’s cardiovascular system so that it can clog the blood vessel or other channel in the patient’s body.

Although preferred embodiments of the present invention have been described, it should be understood that various changes, adaptations, and modifications can be made therein without departing from the spirit of the invention and the scope of the appended claims.

Claims (31)

1. A method of manufacturing a medical device for use in plugging a vessel, canal, lumen or cavity in the cardiovascular system of a person or animal, comprising the following steps:
a) weaving a plurality of metal filaments having a shape memory property into a tubular metal mesh to form a woven configuration;
b) securing at least one end of the net to prevent it from unraveling;
c) the location of the mesh in or on the molding structure of a first predetermined shape containing a plurality of enlarged volume segments having a spherical or oval shape, joined together in a chain by means of intermediate articulating links;
d) heating the molding structure to an elevated temperature for a period of time sufficient to heat shrink the mesh in a first predetermined form to maintain the first predetermined shape when the medical device is in a relaxed state; and
g) shaping a second predetermined shape to the metal mesh including the first predetermined shape by folding around itself to maintain a second predetermined shape when said device is in a relaxed state. 2. The method according to claim 1, where the second predetermined shape is a spiral winding of many turns. 3. The method according to claim 2, where the spiral winding has turns of a relatively relatively small and relatively large diameter. 4. The method according to claim 2, where the spiral winding contains many internal coils inside the Central hole of many external coils. 5. The method according to claim 1, where the stage of giving the second predetermined shape to the metal mesh contains:
a) providing a molding part having a second predetermined shape;
b) placing a mesh with a first predetermined shape in or on a molding part having a second predetermined shape;
c) heating the mold to a temperature and for a time sufficient to heat-shrink the medical device into a second predetermined shape. 6. The method according to claim 1, where the stage of giving the second predetermined shape to the metal mesh contains the following stages:
a) providing a wire thread of metal with a shape memory whose length is substantially equal to the length of said chain;
b) thermally shaping the wire thread to a desired second shape; and
c) stringing a chain on a wire thread. 7. The method according to claim 6, where the wire thread is thermally shaped like a spiral winding of many turns. 8. The method according to claim 7, where the spiral winding has turns of variable relatively small and relatively large diameter. 9. The method according to claim 7, where the spiral winding includes many internal coils inside the Central hole of many external coils. 10. The method according to claim 6, where the wire thread is thermally shaped so that the medical device takes a spherical shape when stringing a chain on a wire thread. 11. The method according to claim 1, where the metal strands have a diameter in the range from 0.001 to 0.006 inches. 12. The method according to claim 1, further comprising the step of longitudinally stretching the chain to reduce the transverse dimensions of the chain. 13. The method according to claim 6, further comprising the step of longitudinally stretching the chain to reduce the transverse dimension exhibited by the second predetermined shape. 14. The method according to claim 1, wherein the step of securing at least one end of the mesh to prevent it from unwinding comprises the step of attaching the clamping member to the opposite end. 15. The method of claim 14, further comprising the step of attaching the clamping member separately to both opposite ends. 16. The method according to 14, where the clamping element includes means for attaching it to the delivery device. 17. The method according to claim 1, additionally containing the following stages:
a) providing a tubular delivery catheter having a proximal end, a distal end and a lumen extending between them;
b) longitudinal stretching of the chain to reduce the transverse size of the chain; and
c) loading the chain into the lumen of the catheter for delivery. 18. The method according to claim 6, additionally containing stages:
a) providing a tubular delivery catheter having a proximal end, a distal end and a lumen extending between them;
b) longitudinal stretching of the chain to reduce the transverse size of the chain; and
c) loading the chain into the lumen of the catheter for delivery. 19. The method according to claim 6, further comprising the step of attaching the clamp to the wire thread and to metal strands containing a mesh at only one end of the metal strands. 20. A medical device for use in plugging a vessel, canal, lumen or cavity in the cardiovascular system of a person or animal, comprising:
a) a braided tubular mesh containing a plurality of braided metal bundles of shape-memory alloy with an expanded predetermined shape in a relaxed, non-compressed state and in a compressed state when it is longitudinally stretched for delivery through a catheter;
b) wherein said expanded predefined shape is a woven mesh deformed to fit the molding surface and comprises a first predetermined shape rolled around itself into a second predetermined shape, where the second predetermined shape is retained when said device is in a relaxed, non-pressed state, and when this first predetermined shape contains many segments of increased volume, having a spherical or oval shape, connected together in a chain dstvom intermediate articulation units of smaller transverse dimension than the transverse dimension larger volume segments. 21. The medical device according to claim 20, where the expanding, predefined shape has the specified chain, which is given the shape of a spiral. 22. The medical device according to claim 20, where the expanded, predetermined shape has the specified chain, which is given the shape of a spiral of many turns with a variable first and second diameter. 23. The medical device according to claim 20, where the expanded, predefined shape has the specified chain, which is given the shape of a spiral winding, which contains many internal turns inside the Central hole of many external turns. 24. The medical device according to claim 20, where the expanded, predefined shape has the specified chain, which is given the shape corresponding to the shape of the vascular cavity to be filled. 25. The medical device according to claim 20, where the specified chain is strung on a shape-determining wire. 26. The medical device of claim 25, wherein the shape-determining wire is a metal alloy exhibiting shape memory properties. 27. The medical device according to claim 26, further comprising means for collecting and securing the braided metal strands at one end thereof to prevent the mesh from loosening, and wherein the shape-determining wire is also secured by means for collecting and securing. 28. The medical device according to item 27, where the means of collection and securing are the first clamp attached to the proximal end of the medical device. 29. The medical device according to p, where the first clamp contains a screw connection for connection to a delivery device. 30. The medical device according to clause 29, further containing a second clamp attached to the distal end of the chain. 31. The medical device according to claim 20, where at least one of the segments of the increased volume contains a polyester mesh.

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